The chemical composition and biological value of two dicalcium phosphates, a dihydrated one (FA) and a monohydrated product (FB), were assessed in a 2 x 3 factorial arrangement of treatments: two phosphates (A and B) and three levels of available P (aP) in the diets (0.22, 0.31 and 0.49%). One hundred and ninety two day-old male broiler chicks (Hubbard) were distributed between 6 treatments with 4 replicates each. During the experimental period (1-42 days), the birds were fed 2 diets: "starter" (1 to 21 days) and "finisher" (22 to 42 days). Feed and water were supplied ad libitum. The phosphates were chemically analyzed for Ca, P, V, Cd, Al and F. FB had a higher P content than FA; and contained concentrations of the contaminants F, Cd, V and Al that were not detected in FA. Body weight, feed intake and feed conversion index were determinal in the chicks on days 21 and 42. At the completion of the study the absolute biological values of the phosphates were calculated, and the length, width, breaking strength and ash contents of the tibias of each bird were determined. There were no differences (P > 0,05) in body weight, feed intake, feed conversion, tibia length and tibia width between FA_ and FB_ fed chicks for the whole experiment. Significant (P < 0.05) differences in body weight, feed intake, tibia length, tibia width, tibia ash content, tibia breaking strength and absolute biological value were present betweer different dietary levels of aP. The two higher levels evaluated did not show significantly different effects (P > 0,05). The similarity of results obtained between the 2 higher levels of aP, showed that the 0.31% level is sufficient under practical conditions which has commercial and environmental importance